The present invention relates to a joint used to connect together two synthetic resin corrugated pipes each including a pipe wall which comprises a sectionally square wall portion and a sectionally circular wall portion alternately in the axial direction of the pipe as well as an annular-shaped projecting strip portion formed in the sectionally circular wall portion.
Conventionally, there are known various types of synthetic resin corrugated pipes and also there are manufactured and used various types of connecting joints suitable for connection of the respective pipe structures of such synthetic resin corrugated pipes. These joints can be roughly classified into a synthetic resin corrugated pipe whose main body is formed in a cylindrical shape and a synthetic resin corrugated pipe which includes at least two main bodies formed as at least two split bodies. The present invention relates to the latter type of joint including at least two split main bodies.
Both of the conventional pipe joints of a cylindrical main body type and of at-least-two-split-main-body type have a diameter larger than the outer peripheral diameter of pipes to be connected together by the pipe joint or have a size larger than the outer peripheral shape of such pipes. That is, either of the conventional pipes joint has a shape which projects outwardly of the outer peripheries of the pipes to be connected together by the pipe joint.
Thus, after the two pipes are connected together by the joint, the connected portions of the pipes become larger in size. For this reason, it is rather considered as common knowledge that, at least in the portions of the pipes where the joint is present, a plurality of pipes cannot be arranged side by side or on top of one another in such a close contact manner as in the non-connected portions of the pipes.
As described above, the present invention relates to a joint used to connect together two synthetic resin corrugated pipes each including a pipe wall comprising a sectionally square wall portion and a sectionally circular wall portion alternately formed in the axial direction of the pipe as well as an annular-shaped projecting strip portion formed in the sectionally circular wall portion. That is, it is an object of the invention to provide a joint which, even in case where the joint connects two pipes together, does not project from the outer peripheries of the pipes to become larger in size than such pipes outer peripheries in the connected portions of the pipes. Also, it is another object of the invention to provide a method for connecting together the pipes of the above-mentioned type using a joint according to the invention, in which a plurality of pipes, even in case where they have portions that are connected together by the joint, can be arranged side by side or piled up on top of one another in the connected portions thereof in such a close contact manner as in the non-connected portions thereof.
Now, describing the structure of the invention employed to attain the above objects using reference characters used in the following description of the preferred embodiments of the invention, for connection of a synthetic resin corrugated pipe P in which a pipe wall 1 comprises a sectionally square wall portion 2 and a sectionally circular wall portion 3 formed alternately in the axial direction of the pipe P, while the sectionally circular wall portion 3 includes an annular-shaped projecting strip portion 4, there is provided a joint which comprises: two synthetic resin joint main bodies 10 respectively comprising two semicircular-shaped split bodies; and, two watertight packings 20 respectively formed of elastic material, while each packing 20 includes two flanges 22, 22 respectively projecting from the two end portions of a semicircular portion 21 of the packing 20 in the outer peripheral direction thereof. Each joint main body 10 is structured such that, except for its two side edge portions 14, 14 in the width direction thereof, it is formed as a recessed groove 13 for receiving its associated packing 20 and includes tightening bolt holes 15, 15 respectively formed in the two end portions 12, 12 of the main body 10 in the peripheral direction thereof. And, each watertight packing 20 is structured such that the width-direction central portion of a semicircular-shaped portion 21 thereof is formed as a projecting portion 23 projecting on the inner surface side thereof and the two side edge portions of the packing 20 are respectively formed as recessed portions 24, 24 recessed on the outer peripheral surface side of the packing 20. Also, in a state where the packing 20 is mounted into the joint main body 10, the two side recessed portions 24, 24 are recessed more deeply on the outer peripheral surface side of the joint than the two side edge portions 14, 14 of the joint main body 10, and the surface portions f, f of the two end portions of the packing 20 in the peripheral direction thereof project further outwardly of the surface portions F, F of the two end portions 12, 12 of the joint main body 10 by a proper thickness t.
Also, according to the invention, there is provided a method for connecting a synthetic resin corrugated pipe P in which, as described above, a pipe wall 1 comprises a sectionally square wall portion 2 and a sectionally circular wall portion 3 formed alternately in the axial direction of the pipe P, while the sectionally circular wall portion 3 includes an annular-shaped projecting strip portion 4. In the present connecting method, using a joint which comprises two synthetic resin joint main bodies 10 respectively comprising two semicircular-shaped split bodies and further includes tightening bolt holes 15, 15 respectively formed in the two end portions 12, 12 of each main body 10 in the peripheral direction thereof, the respective ends of two pipes P, P to be connected together, after they are cut except for the annular-shaped projecting strip portions 4 of the sectionally circular wall portions 3 of the two pipes P, P, are butted against and connected to each other while the sectionally square wall portions 2 of the two pipes P, P are held at the same posture in the peripheral direction thereof; two watertight packings 20 are respectively inserted into the connected portions of the two pipes P, P; and, the two joint main bodies 10 are tightened and connected together on the diagonal line of the sectionally square wall portions 2 of the two pipes P, P to thereby connect together the two pipes P, P.
Further, the above-mentioned object can be attained by a joint for connection of synthetic resin corrugated pipesP, according to the present invention, each of the corrugated pipes including a pipe wall 1 which comprises a sectionally retangular wall portions 2 and a sectionally circular wall portions 3 disposed alternately in a longitudinal direction of the corrugated pipe wherein each of the sectionally circular wall portions 3 includes an annular-shaped protrusion 4 which projects outwardly from the sectionally circular wall portions that is disposed substantially at a center of the sectionally circular wall portion between adjacent sectionally rectangular wall portions in the longitudinal direction, the joint comprising:
a pair of semicircular-shaped joint main bodies 10 coupled with each other by bolts, each having a recessed groove 13 defined by its both side edge portions 14, 14 in a width direction thereof and also having tightening bolt holes 15, 15 respectively formed at both peripheral end portions 12, 12 in a peripheral direction thereof; and
a pair of watertight packings 20 respectively formed of elastic material and respectively received in the recessed grooves 13 of the semicircular-shaped joint main bodies 10, each of the watertight packings 20 having a semicircular portion 21 which includes two edge portions 24, 24 disposed at two end portions in a width direction thereof, and a projecting portion 23 disposed between the two edge portions in the width direction and inwardly projected in a radial direction of the pipe,
wherein a thickness of each of the two edge portions 24, 24 in the radial direction is smaller than a height of the side edge portion 14 in the radial direction, whereby, in a state where each the packings20 is mounted into the respective joint main bodies 10 and the joint joints the pipes, two side recessed portions 24 into which the annular-shaped protrusions 4 of the pipes are respectively received are formed by the two edge portions 24, 24, and
wherein the surface portions f, f of the two end portions of the packing 20 in the peripheral direction thereof project further outwardly of the surface portions F, F of the two end portions 12, 12 of the joint main body 10 by a predetermined thickness t, and
wherein each of the watertight packing 20 further comprises flanges 22, 22 disposed at two end portions of the semicircular-portion 21 in a peripheral direction thereof and outwardly projected in the radial direction.
In the joint, the joint main body 10 may be formed as a semicircle slightly shorter than a regular semicircle.
In the joint, the joint main body 10 may be formed substantially identical with or smaller in size than the outer peripheral shape of the sectionally rectangular wall portion 2 of the pipe P.
In the joint, the watertight packing 20 may include, on the inner surface of the projecting portion 23, two ribs r, r respectively extending along the peripheral direction of the packing 20 and inwardly projecting in the radial direction of the pipe.
Further, in the joint, the watertight packing 20 may include, on at least one of the two end portion surface portions f, f, a rib R formed so as to terminate toward the inner surface side of the projecting portion 23 of the packing 20.
In the joint, it it preferable that the predetermined thickness t of the watertight packing 20 is set in the range of 0.1-1.0 mm, more preferably in the range of 0.2-0.5 mm.
Furthermore, in the joint, each of the recessed grooves 13 may comprise a projecting beam 13a which is formed at its intermediate portion in the width direction thereof and is inwardly projected in the radial direction of the pipe.
Moreover, in the joint, each of the semicircular-shaped joint main bodies preferably comprises recessed step portions 16 which are disposed at two peripheral ends thereof for receiving the respective flanges 22, 22 of the packing 20.
In addition, in the above-mentioned joint, the thickness of each of the flanges in the peripheral direction is preferably larger than that the depth of each of the recessed step portions in the peripheral direction, in a state where each of the packings 20 is mounted into the respective joint main bodies 10.
The above-mentioned object can also be attained by a method for connecting a pair of synthetic resin corrugated pipesP, according to the present invention, each of the corrugated pipes including a pipe wall 1 which comprises a sectionally rectangular wall portions 2 and a sectionally circular wall portions 3 disposed alternately in a longitudinal direction of the corrugated pipe wherein each of the sectionally circular wall portions 3 includes an annular-shaped protrusion 4 which projects outwardly from the sectionally circular wall portions that is disposed substantially at a center of the sectionally circular wall portion between adjacent sectionally rectangular wall portions in the longitudinal direction, the corrugated pipe connecting method comprising the steps of:
preparing the pair of the pipes each of which is cut into a predetermined length at a portion of the sectionally circular portion in a plane substantially perpendicular to an axis of the pipe while remaining the annular-shaped projecting strip portions 4,
abutting the cut portions of the pipes each other, and holding them at the same posture in the peripheral direction thereof;
putting a joint on the connected portions of the pair of pipes P, P wherein the joint comprises a pair of joint main bodies 10 respectively made of two semicircular-shaped split bodies each having tightening bolt holes 15, 15 formed in its two end portions 12, 12 of the main body 10 in the peripheral direction thereof, and a pair of watertight packings 20; and
fastening bolts inserted in the tightening bolt holes 15, 15 and then connecting the two joint main bodies 10 together on the diagonal line of the sectionally rectangular wall portions 2 of the two pipes P, P, to thereby joint together the two pipes P, P.